JNR Class EF63

Class EF63

A pair of EF63s leading a 489 series EMU on a Hakusan service in June 1997

Type and origin Power type Electric Builder Kawasaki, Mitsubishi and Tōshiba Build date 1962–1976

Specifications UIC class Bo-Bo-Bo Gauge 1,067 mm (3 ft 6 in) Wheel diameter 1,120 mm (3 ft 8 in) Length 18,050 mm (59 ft 3 in) Width 2,800 mm (9 ft 2 in) Height 4,060 mm (13 ft 4 in) Loco weight 108 t Electric system(s) 1,500 V DC Traction motors DC

Performance figures Maximum speed 100 km/h (62 mph) Power output 2.55 MW (3,420 hp) Tractive effort 23,400 kgf (229,476 N; 51,588 lbf)

Career Operators JNR, JR East, JR Freight Number in class 25 Disposition All withdrawn

The Class EF63 (EF63形^?) is a class of 1,500 V DC electric locomotives formerly operating in Japan.

A total of 25 Class EF63 locomotives were built between 1962 and 1976 exclusively for use as bankers (U.S. "helpers" or "pushers") on the steeply-graded Usui Pass section of the Shinetsu Main Line between Yokokawa and Karuizawa. They replaced the Class ED42 electric locomotives previously used on the rack-and-pinion line between these two stations.

The prototype, EF63 1, was produced in 1962 by Toshiba for testing before full production of the class started in 1963 spread between manufacturers Kawasaki, Mitsubishi and Toshiba. The class was equipped with a number of special safety features to cope with the unique conditions of operating on the 66.7‰ gradient of the Usui Pass. These included independent dynamic brakes on all six axles (hence the large louvres along the bodysides for heat dissipation), magnetic adhesion brakes operating directly on the rails, and mechanical locking brakes. Small wheels attached to the centre bogie were used to measure the train speed and apply the brakes in the case of run-away. The class used the same 425 kW MT52 traction motors used on the EF62s and also the EF70s. The entire class was based at Yokokawa depot, and they were always used in pairs at the Yokokawa end of trains travelling in both directions, and were capable of operating in multiple with Class EF62 locomotives and a wide range of EMU types (including 115, 185, 189, 489 series) – hence the impressive array of jumper cables and connectors on the Karuizawa ends of the locos. Trains ascending the incline from Yokokawa were driven by the driver in the rearmost cab of the EF63 pair at the rear of the train, with the driver in the front cab of the train acting only as signal look-out.